1. Field of the Invention
This invention relates to a device for displaying whether a camera is loaded or unloaded with film as well as indicating when the film is being either advanced or rewound.
2. Description of the Prior Art
Many previous proposals have been made for preventing loaded film in a camera from being exposed as the back cover is unintentionally opened. For example, Japanese Utility Model Publication No. SHO 42-18571 discloses a method for displaying whether or not the camera is loaded with film by putting a colored warning plate into a window provided on the outer panel of the camera housing when the presence of film on the tape-up spool is detected. There also exists a warning method by which a display member is projected into the frame counter window. Another method works such that, the frame counter is rendered operative only when the film is loaded. In another foolproof method, the back cover of the camera is automatically locked after the film leader is wound off. In still another foolproof method, the winding operation is able to be performed only when the film is properly loaded.
Since any one of these known prior methods operates the display member through a mechanical intermediary element, the use of these methods leads to an increase in the number of parts and the production cost. Because little space is available within the camera, the display must be located as near as possible to the film or cartridge detector.
There have also been many previous proposals for displaying when film is being transported. For example, Japanese Laid-Open Utility Model Application No. SHO 53-36331 and Japanese Laid-Open Patent Application No. SHO 56-24234 disclose such systems. Since these systems are also mechanical, it is necessary to arranged such displays adjacent the detector.
It has been impossible to construct a common display indicating the presence or absence of the cartridge as well as whether or not film is being transported across the exposure gate. For this reason, in checking whether or not the camera is empty, or if the film is properly loaded and advanced for each frame, the photographer has to check each different display at a different place despite the fact that all of this information is film-related. These successive operations for assuring the state of the film at any given time have caused great annoyance to most photographers.
Since the loading and feeding are displayed in different forms, there has also been some confusion for beginners when the displays are read, regardless of the type of presentation of these displays.